1. Field of the Invention
The present invention relates to scientific instrumentation. More particularly, the present invention relates to microtiter plates and test tube racks.
2. Description of the Related Art
The standard 96-well test tube racks and 96-well microtiter plates are a workhorse in the life science, biotechnology, and pharmaceutical industry. Under the specifications of the industry standard defined by the Society for Biomolecular Screening (SBS), the 96 wells are arranged in a rectangular matrix of 8 rows×12 columns, with a pitch size of 9 mm. The overall dimensions of the plate are defined by its outer skirt, which is 127.6 mm×85.3 mm. Higher-density plates are based on this basic design, with the outside, skirt dimensions being maintained constant while the pitch size is reduced by ½ for 384-well plates, by ¼ for 1536-well plates and by ⅙ for 3456-well plates.
The usefulness of these items is significantly extended by the existence of array pipetters equipped with 96 or 384 tips that are arranged in rectangular matrices of 8×12 or 16×24 with pitch sizes of 9 mm or 4.5 mm, respectively. With these devices, pipetting into and out of multi-well plates can be done in a parallel, high-throughput fashion. Much of high-throughput screening relies on the joint application of these plate and pipetting technologies.
A drawback with SBS standard devices is that their fixed geometry and size may not be amenable for use with a variety of scientific instrumentation. Thus, there is a need for a more flexible design that still offers the benefits associated with using SBS standard array pipetters.
One example where the size of SBS standard racks and plates limits their use is in centrifugation. In many applications, it is often necessary to centrifuge the tubes or plates. There are numerous centrifuges that work with these devices that use swinging bucket rotors. The plates or racks are deposited into these rotors in the upright position. When the rotor starts spinning, the buckets swing up and the plates or racks are centrifuged horizontally. This technology only allows for low-g centrifugation. These plate centrifuges perform in the range of 2000 g, which is only enough to gently pellet cells. However, in applications where much tighter pellets are required, e.g., clearing of protein precipitates, much higher centrifugation in the range of 10,000-20,000 g is needed. Thus, there is a need for devices and methods that provide the option of high g centrifugation of multiple samples.